Incandescent gas burner for furnace walls



Jne 28, 1949. F. o. HEss 2,474,313

INCANDESCENT GAS BURNER FOR FURNAGE WALLS med oct. -25. 194s 4 sheets-sneer 1 IN VEA/TGR i w/T/veas "Y Q .Arran/vtr Jung 28, 1949. F, o. HEss' 2,474,313

INCANDESCENT GAS BURNER lFOR FURNACE WALLS Filed Oct. 25, 1945 4 Sheets-Sheetv 2 I oRn/Ef June 28', 1949. Fgo. HEsS 2,474,313

` rncANDEscENT GAS BURNER Fon FURNAcE wALLs I Filed 06t- 25, 1943 E-VQQ 9. n ad' 4 Sheets-Sheet 3 wl TNES'S Y QM HTTURNEY June 28, 1949. F o, HEss 2,474,313

'ICANDESCENT GAS BURNER FOR FURNACE WALLSi Filed oct. 25. 194:5 '4"`shetssneet 4 /NvE/VTOR N11-Nass, u y I BY ,Jn-rrcmvws:

Patented vJime 28; 1949 INCANDESCENT GAS BURNER FOR' FURNACE WALLS Frederic 0. Hess, Philadelphia, Pa., assigner to Selas Corporation of America, a corporation of Pennsylvania Application october 25, 1943, serial No. 507,492

(el. 15s- 7) 11 claims. l

My invention relates to gas burners, and more vparticularly to burners having a distributor for sub-dividing a combustible gas mixture into a plurality of streams and at a surface of which a plurality of flames are produced and maintained. This application is a continuation-inpart of application Serial No. 365,440, filed November 13, 1940 and now abandoned.

Although not to be limited thereto, my improved distributor for gas burners is especially useful in a burner of the kind described and illustrated in Hess Patent No. 2,215,079 granted on September 17, 1940, and assigned to the same assignee as this application. WhileI the abovementioned patent discloses a distributor for Aa burner which is satisfactory for most uses, there are a few special instances in which the burner distributor is sometimes troublesome in operation. This is especially true when slow burning natural gases are used, for example, in which case there is an occasional ignition failure when the burners are being operated at relatively low capacity and at reduced temperature. When distributors of the character heretofore provided are used in burners for heating furnaces, such distributors are satisfactory in most cases. However, when materials are being heated from which vapors are expelled and such vapors condense on the distributors and form a deposit, such as glaze, for example, objectionable clogging of the gas passages may result.

It is, therefore, anv object of my invention to provide an improved burner provided with a distributor capable of maintaining ignition even when the latter is being operated at reduced capacity, and particularly when using slow burning natural gases or other gases of a similar nature.

Another object of my invention is to provide an improved distributor of such shape that the outlets of the slots or passages formed therein, and from which the gas streams are discharged, are protected from any matter tending to deposit thereon at the regions between the slot outlets.

A further object of my invention is to provide an improved distributor having slots or passages formed therein of such shape that the velocity of the gas mixture owing through the passages is reduced before issuing from the discharge ports, thereby insuring a velocity of the gas mixture in the greatest part of the passages which is beyond the range of flame propagation while the velocity of at least a part of the gas mixture at the outlet ends of the passages -and just before issuingJ from the discharge ports is within the range of ame propagation.

A still further object of my invention is to provide a distributor having the slots or passages formed so that streamline ow of the individual gas streams is effected as the streams issue from the distributor slots, whereby the regions at the vicinity of the slot outlets are always in an environment filled by the issuing gas streams and re-circulated gases containing objectionable deposit forming vapors cannot be drawn toward and come in contact with the surfaces of the distributor and form a deposit at the immediate vicinity of the slot outlets or discharge ports.

A still further object of my invention is to provide a distributor for a burner having a refractory wall associated therewith, in which improved heating of the refractory wall to incandescence is effectedy by a plurality of flames maintained at the surface of the distributor, thereby increasing the temperature of the refractory wall which serves as a source of radiant heat.

The invention, together with the above and other objects and advantages thereof, will be more fully understood upon reference to the following description and the accompanying drawings forming a part of this specification, and of which:

Fig. 1 is a sectional view of a furnace provided with burners embodying the invention;

kFig. 2 is an enlarged sectional view of one of the burners shown in Fig. 1 to illustrate the burner structure more clearly;

Fig. 3 is an enlarged sectional View of thel burner distributor shown in Fig. 2 to illustrate the shape of the distributor and also several oi the slotted passages therein;

Fig. 4 is a view similar to Fig. 3 illustrating the distributor in elevation;

Fig. 5 is an end view of the burner distributor shown in Fig. 4, Vlooking at the distributor from the tapered or pointed end toward the opposite enlarged end;

Figs. 6 and 7 are views similar to Figs. 3 and 4 illustrating another embodiment of the invention;

Fig. 8 is a View generally similar to Fig. 5 and taken at Eine 3-8 of Fig. 7;

Fig. 9 is a horizontal plan view of a furnace provided with elongated burners illustrating a further embodiment of the invention;

Fig. 10 is a sectional view of one of the burners diagrammatically illustrated in Fig. 9;

Fig. 11 is an enlarged sectional view of a burner distributor, taken at line I I-II of Fig. 12, illustrating a still further embodiment of the invention;

Fig. 12 is a vertical sectional view of the burner distributor shown in Fig. 11;

Fig. 13 is an end view of the burner distributor of Fig. 12 looking toward the enlarged end thereof, and partly broken away and in several fragmentary sections including that taken at line 13-13 of Fig. 12;

Fig. 14 is a sectional view similar to Fig. 12, illustrating a still further vention; and

Fig. 15 is an end view of the burner distributor of Fig. 14 looking toward the enlarged end thereof, and partly broken away and in several fragmentary sections including that taken at line I5-I5 of Fig. 14.

Referring to Fig. 1, burners I0 provided with distributors embodying the invention are mounted and incorporated in the side walls Il of a furnace i2. The furnace l2 is formed with a roof I4 and a oor i5 which is supported by a foundation I6 on a supporting surface. The material I1 to be heated within the furnace l2 may be mounted on a car I8 which is moved slowly through the furnace chamber I9 on a track 20.

The burners I0 are arranged at different elevations and distributed lengthwise of the side walls il, the number of burners and distribution being such that desired heating is effected of the material I1 passing through furnace chamber I9.

The burners I0 are mounted in and form a part of the side walls Il. As shown most clearly in Fig. 2, each burner i0 comprises a molded block 2i of ceramic material which is secured in position in one of the side walls il by a suitable high temperature fire-brick cement 22. The blocks 2l may have different portions thereof formed of refractory materials possessing different heat resisting and thermal conducting properties, so that each portion will possess the most desirable heat resisting and thermal properties for its particular position in the block. The different portions of each block are compacted into a single unitary structure by a suitable molding operation to provide the blocks 2l which are rectangular in cross-section.

The blocks 2| are formed with central passages 23 which extend therethrough and terminate at cup-shaped spaces 2t formed at the inner faces of the side walls Il. Within the passage 23 is disposed a burner tube or sleeve 25 having the inner end thereof terminating at a regon closely adjacent to the inner end of the passage 23. The outer portion of tube 25 is formed with an outwardly extending shoulder 26 which fits snugly against a collar 21. The collar 21 may be a pre-formed and pre-fired body' of porcelain which is thereafter united to the block 2i at the same time that the different portions of a block are united together by a firing operation. In order to position the tubes 25 accurately in the passages 23, the surfaces of the collars 21 engaged by the shoulders 26 may be ground after the blocks 2l are formed. The shoulder 26 of each tube 25 is positioned in an enlarged opening or well 28 extending from the outer end of passage 23 to the outer face of the side wall il. Within the outer end of burner tube 25 is secured the inner end of a metal tube 29, as by cement, for example.

The outer end of each metal tube 28 is secured to the inner end of a short length of flexible embodiment of the in- 4 tubing 30 which is fastened at its opposite end to the inner end of an internally threaded opening 3l formed in a hollow cover plate 32. Within the hollow cover plate 32 is provided a helical coil spring 83 which is arranged to exert force against the outer end 34 of shoulder 28. In this way the shoulder 28 will always snugly press against the collar 21 irrespective of the relative expansion of the different burner parts over the wide temperature range encountered during operation of the furnace l2. The cover plate 32 is sulciently large to close the enlarged opening or well 28 and isA secured at 35 to the outerv metallic shell 36 of the furnace l2.

A suitable combustible mixture is delivered from a source of supply through conduits 31 connected to the internally threaded openings 3l of the burners l0. The conduits 31 for supplying combustible gas mixture to the burners l0 may be arranged in any desirable manner, and suitable controls may be provided to adjust the pressure and the rate at which the combustible gas mixture is supplied to each burner I8. In each burner I0 the combustible gas mixture passes through the short length of flexible tubing 38 and metal tube 29 into the burner tube 25.

At the inner end of each tube 25 is secured a distributor 38 for sub-dividing the combustible gas mixture into a plurality of gas streams which are discharged from a surface of the distributor and at which region a plurality of burner flames are produced and maintained. The burner flames project outwardly from the distributor 38 about the entire peripheral surface thereof. The combustion space 2l is of such shape and the flames project outwardly at such an angle from the axis of the burner that the flames are closely adjacent to and follow the cup-shaped refractory wall to heat the latter to incandescence.

The distributors 38, which are preferably formed of high temperature refractory material, are so positioned at the inner ends of the tubes 25 that the inner cones of the individual flames will always be out of contact with the wall surface irrespective of the lengths of the flames. The relationship of the angle of divergence of the individual llames and the shape of the wall of the combustion space 24 is fully disclosed in the aforementioned Hess patent which may be considered as being incorporated in this application, and, if desired reference may be had thereto for a more detailed description of the burner structure. In order to increase the combustion space wall area and the amount of radiant heat emitted therefrom, especially when the burners are being operated at reduced capacity, the walls of the combustion chamber spaces 24 are formed lwith ribs 39. This is clearly described and illustrated in Hess and Ehlinger application Serial No. 373,728, led January 9, 1941, now Patent No. 2,339,477 granted January 18, 1944.

In accordance with my invention, the distributors 38 are of such shape that the likelihood of flame extinction is minimized when the burners I0 are being operated at relatively low capacity, and at the same time the shape of the distributor is such that the distributor passages are protected from matter which tends to deposit thereon in certain uses of the burners. As shown most clearly in Figs. 3 and 4, each distributor 38 includes a cylindrical body portion 40 which is tapered at one end at 40' to facilitate the subdividing of the combustible gas mixture into a plurality of gas streams.

The periphery of the body portion 40 is threaded at 4I so that the distributor may be accurately secu-red in position at the internally threaded inner end 42 of the burner tube 25. Immediately adjacent to and joining the body portion 40 is a rst enlarged head portion 43 having a straight-sided wall part substantially .parallel to the axis of the distributor, and an inclined or beveled wall part extending inwardly f-romthe straight-sided wall part to the body portion 40.

Immediately adjacent to the rst enlarged head portion 43 is 'a second enlarged head portion 44 more remote from the body portion 40 than the first enlarged head portion 43. The second and innermost enlarged head portion 44 may be slotted at 45 to facilitate the insertion and removal of the distributor 38 int-o and from the threaded inner end of theburner tube 25.

The extreme inner end of the burner tube 25 is beveled at 46, and, when the distributor 38 is threadedly secured in position, ythe inclined or beveled part of the iirst enlarged head portion 43 bears and ts snugly against the beveled surface 46, so that the distributor 38 Will be accurately positioned in the cup-shaped combustion chamber space 24.

The main body portion 40 and rst enlarged head portion 43 are formed with a plurality of slots 41 extending lengthwise of the distributor 38 from the tapered end 40' to the underside of the second enlarged head portion 44, as shown most clearly in Figs. 3 and 4. The slots 41 are distributed about the periphery of the body portion 40 and rst enlarged head portion 34, and are of uniform depth from the tapered end 40 to the rst enlarged head portion 43, las shown most clef rly in Fig. 3. The bottom walls of the slots 41 are inclined outwardlyat the rst enlarged head portion 43 and are substantially parallel to the beveled or inclined end 4-6 of the burner tube 25.

It will now be understood that the three-sided slots or grooves formed in the distributor 38 and the inner wall surface of the burner tube 25 together form the passages 41 into which the combustible gas mixture iiows to sub-divide the gas mixture into a plurality of gas streams. The only portions of the slots, which are not covered and are exposed, are the portions 48 at the straightsided outer part of the ilrst enlarged head portion 43. The portions 48 just referred to constitute the ports or discharge orifices from which the individual gas streams =are discharged, and it is at these regions that the burner flames are produced and maintained.

The second and innermost enlarged head .portion 44 extends laterally or radially beyond the discharge orifices or ports 48, as indicated at 49 'in Fig. 4. In some cases the lburner tube 25 and passage 23 formed in the burner :block 2| may be of such size that the entire burner unit including the distributor 38 may be inserted into and withdrawn from a furnace wall as a complete assembly. However, it may be desirable in many cases to employ -distributors 38 in which the innermost enlarged head portion 44 extends radially outward to such an extent that it cannot be inserted into position or withdrawn therefrom through the passage 23, and in such cases the distributor 38 may be secured into `and removed from the inner end of the tube 25 from within the furnace chamber.

During operation of the burner l0, the gas flames project outwardly from the discharge orices 48 at an inclined angle from the burner axis, as pointed out above and diagrammatically indicated at 50 invFig. 3. By providing the second and innermost enlarged head Iportion 44 on the distributor 38, the individual gas ames brush against and come in contact with the underside and outer peripheral surface portions of the 'lateral projection 49, thereby heating these regions to incandescence. The incandescent regions produced at the lateral projections 49 are highly beneficial in maintaining ignition of the combustible gas mixture issuing from the ports 48, and this is especially true when the burners are being operated at -relatively low capacity and at reduced temperature. It has been found that when .burners provided with distributors 38 like those described and illustrated are being operated with a slow burning gas, such as natural gas high in methane, for example, reliable ignition is obtained under all operating conditions. -In addition, the lateral projections 49 improve ignition of Vslow burning gases by eiecting a change in the velocity curve 'of the combustible gas mixture issuing from the ports or discharge oriiices 48. This is clearly shown in Fig. 3 by the fact that the iiame 50 is deflected by brushing against the underside of the enlarged head portion 44. Further, the underside of the enlarged head portion 44 offers frictional resistance tothe combustible gas mixture brushing and coming in contact therewith, thereby having a tendency also to reduce the velocity of the gas mixture.

The second and innermost enlarged head portion 44 also provides a protective skirt about the ports 48. The vapors produced when certain materials are being heated in a furnace have a tendency to condense and form a deposit at regions between the ports 48 in distributors of the kind heretofore provided. This is -due to the fact that these regions, indicated at 5| in Fig. 4, are zones which a-re at a reduced pressure and low temperature, so that objectionable condensing of vapors tends to occur at these places and form a deposit which may eventually accumulate to such an extent that the .ports 48 becomes clogged. It is to be noted that this only occurs when objectionable vapors are present tending to form such deposits. However, the protective skirt formed by the lateral projection 49 prevents the free and unobstructed ow of objectionable vapors to the regions v5|, which reduces to a marked degree the depositing of matter in the vicinity of the ports, and any deposits will then tend to take place on the top surface-of the innermost enlarged head portion 44 which is not harmful nor detrimental. f-or continuous and successful burner operation.

In Figs. 6 to 8 inclusive I have shown another form of distributor 38a which Ldiiers from the distributor 38 previously described in that teeth 52 are added about the periphery of the straightsided wall part of the first enlarged head portion 43a. The teeth 52 are tapered and extend radially outward the same distanceas the projection 49a of the innermost enlarged head portion 44a, as shown most clearly in Fig. 8.

By providing tapered teeth 52 at the regions between the passages 41, the portions of the passages at the vicinity of the rst enlarged head portion 43a are extended radially outward the depth of the teeth. Further, the tapered teeth 52 provide discharge orifices or ports 48a having outwardly curved diverging side walls which are extensions of and in communication with the inclined portions of the passages 41 at the vicinity of the beveled end 46 of the burner tube 25. By providing discharge oriiices or ports 48a having curved diverging side walls, a more or less streamline flow of the combustible gas mixture is effected as it is discharged from the passages 41 about the periphery of the distributor 38a.

The ports 48a permit the combustible gas mixture issuing from the passages 41 to expand and completely fill up the ports and also the regions in the immediate vicinity of the tips of the teeth 52, the nature of the gas flow being such that now of gases in the vicinity of the teeth is always radially outward with no objectionable eddy currents being produced between adjacent ports 48a. By causing stream-line `flow of the gas mixture passing from the ports 48a and eliminating eddy currents at the tips of the teeth 52, no regions of reduced pressure and low temperature are produced between adjacent ports 48a at the outer edges of the teeth 52, whereby gases re-clrculating in the combustion chamber space, and which may contain deposit forming vapors when such vapors' are present. cannot come in contact with the distributor surfaces adjacent to the ports 48a and the forming and building up of a deposit is practically eliminated.

When burners provided with distributors 38a are operated with the gas mixture being supplied thereto at a sufficient pressure and at a sufilicient rate, flames are produced at the ports 48a which have a tendency to spread out and push against each other at the regions beyond the extremlties of the teeth 52 and substantially midway between adjacent ports 48a, as diagrammatically indicated at 50a in Fig. 8. This spreading action of the flames is highly beneficial and tends to eiect extremely uniform heating of the walls of the combustion chamber spaces 24 as the iames f project outwardly and follow paths of flow closely adjacent to the cup-shaped refractory walls. This substantially uniform heating of the walls of the combustion chamber spaces is eected even though there is some slight variation in name intensity between the center parts of the flame directly opposite the passages 41, and the parts at which adjacent flames push against each other.

The highest flame intensity is produced at the regions where adjacent flames push against each other, and this can be readily observed by the fact that when operation of a burner is i'lrst started, the surface regions of the refractory wall directly opposite the teeth 52 are rst heated to incandescence. After a short interval of time of burner operation, however, the entire cup-shaped refractory wall rapidly reaches an incandescent temperature, thereby effecting substantially unilform heating ofthe cup-shaped wall in a relatively short interval of time.

Due to the stream-line flow of the combustible gas mixture issuing from the ports 48a and the frictional resistance offered to the gas mixture coming in contact with and brushing against the diverging side-walls of the ports, the velocity of the issuing gas mixture' is reduced considerably. As a result of this reduction in velocity of the issuing combustible gas mixture, it is possible to supply the gas mixture at such a pressure and rate to a burner that the velocity of the gas mixture through the passages 41, from the ta.- pered inlet ends 40' to the regions indicated at 53 in Fig. 8, is beyond the range of flame propagation; while the velocity of at least a part of the gas mixture in the ports 48a and before the gas mixture issues from the distributor is within the range of ame propagation. This is especiaily beneficial in that the likelihood of backre is substantially avoided. and at the same time the 8 flames can be produced and maintained closely adjacent to the ports 48a and in the immediate vicinity of the teeth 52 not only with city gas but also with slow burning natural gases. It has been found that in using distributors generally like the distributor 38a just described, the refractory walls of the combustion chamber spaces 24a are uniformly heated to incandescence with no dark spots at regions about and closely adjacentV to the outer periphery of the distributor. Not only is improved heating of the walls of the combustlon chambers v21m effected, but it has also been observed that the refractory walls are heated to higher temperatures than heretofore possible. This increase in temperature of the refractory walls of the combustion chambers 24a is as much as 200 F. and higher, thereby providing higher temperature sources of radiant heat.

It has already been pointed out that the ports 48a are always filled with the issuing gas streams due to the stream-line ow of the gas mixture being discharged from the ports, and this is the condition that usually obtains when the burners are operated under normal operating conditions. The particular region at which combustion of the gas mixture starts to take place in the ports 48a depends upon the pressure and the rate at which the gas mixture is supplied to the burners. When the pressure and rate at which the gas mixture is supplied to the burners is reduced sufliciently, tiny flames are produced within the ports 48a, and in such cases the flames heat the teeth 52 to incandescence. This promotes and facilitates ignition of the gas mixture when the burners are being operated at a relatively low capacity.

Therefore, when the burners are being used in a furnace and certain materials are being heated that produce deposit forming vapors, 'the distributors 38a can be operated continuously without any objectionable matter depositing thereon, so that the ports 48a and surfaces adjacent thereto will always remain clean and free from any deposits which tend to form when certain deposit forming vapors are present. As in the embodiment previously described, the innermost enlarged head portion 44a serves as a protective skirt for the discharge orifices or ports 48a, thereby providing a burner distributor of desirable shape for all uses and particularly useful when it is necessary to employ a distributor that must be protected from objectionable deposit-forming vapors.

In Figs. 9 and 10 I have illustrated a further embodiment which diifers from the previously described embodiments in that burners Hic of an elongated type are employed to effect heating in a furnace (2c. In Fig, 9, the burners I0c are mounted and incorporated in the side walls llc of the furnace `I2c. The furnace I2C is formed with the usual roof, floor 9c, and end walls 8c having doors 1c. A track 2Go extending through the furnace may be provided for a car similar to that shown in Fig. 1, and upon which is mounted the material to be heated. The burners 10c may be positioned and distributed at the opposing vertical walls llc in any suitable manner to effect desired heating of materials in the furnace chamber I9c. Although the elongated burners lllc are shown in a horizontal position in Fig. 9, it should be understood that the burners may be positioned vertically at the walls Ilcwhen desired.

As shown in Fig. 10, each burner lllc includes a molded block section 53 which may be formed '15 of one or more blocks depending upon the length lsage 23e.

9 of the burner. When the block section 53 is formed from a number of blocks, these blocks are united together and the entire block section then united at 22e to the side wall llc by a suitable high temperature flre-brick cement,

The block sections 53 are formed with elongated passages 23e extending lengthwise of the side walls H c and terminating at the inner face of the side walls at combustion spaces llc. Each combustion space 24c vis cup-shaped in section and includes top and bottom refractory surface portions extending radially outward from the burner axis and toward the inner face of the side wall I I c. The walls of the combustion spaces 24e may be provided with ribs 39e, similar to the ribs 39 in Fig. 2, which extend lengthwise of the furnace sidewalls.

Within each passage 23e of the block section 2lc is positioned a hollow rectangular-shaped burner sleeve 25e which extends between the opposite vertical side walls of the passage 23e. A plurality of relatively thin plates 55, which are stacked together to form a distributor unit 38e which will be described hereinafter, are securely held in any suitable manner to the inner end of burner sleeve 25e. As shown, the plates 55 are formed with lugs 56 which are held against the extreme inner end of sleeve 25e by angle members 5l xed to the sleeve. The inner end of the sleeve 25e and angle members 5l form recesses to receive the lugs 5d of the plates 55. In order to provide atight gas seal, asbestos packing or the like may be employed at 58 between the lugs 54 and vertical arms of the angle members 5l,4 and fire brick cement may be employed at 59 between the lugs 54 and extreme inner end of the sleeve 25e.

The angle members 5l t snugly against a shoulder 66 formed intermediate the ends of pas- Each passage 23e extends from the outer portion of a block section 53 through the furnace wall l l c to the outer face thereofl The outer portion of each burner sleeve 25c passes through an opening formed in a cover plate 32e which is secured at 850 to the outer metallic shell 36e of the furnace l2c. When the cover plate 32e is secured in position, the outer wall 6| of such plate snugly fits against the outer end of the burner sleeve 25C, thereby maintaining the angles 5l at the inner end thereof snugly tting against the shoulder 66. A manifold 62, to which a suitable combustible gas mixture is supplied through a conduit 31e, is secured at 63 to the cover plate 32o. A suitable fire brick cement may be employed at 64 between the outer end of sleeve 25e and the outer wall 6I of the cover plate 32e to provide 'a gas tight seal between these parts.

The combustible gas mixture supplied to each manifold 62 passes therefrom into the burner sleeve 25e. As in the embodiment illustrated in Figs. 1 and 2, the conduits'for supplying the gas mixture to the burners lllc may be arranged in any desirable manner, and suitable controls may be provided to adjust the pressure and the rate at which the combustible gas mixture is supplied to each burner.

The distributor unit 36e positioned at the inner end of the burner sleeve 25e effects distribution of the gas mixture, whereby the gas mixture is discharged from a plurality of ports 65 disposed at opposite side edges of the plates 55. The flames produced at the ports 65 project upwardly and downwardly at such an angle that the llames are closely adjacent to andfollow the top and bottom portions of the refractory wall to heat the latter to incandescence. The distributor 38e is so positioned in the burner that the inner cones of the individual flames always will be out of contact with the wallsurface irrespective of the lengths of the burner llames. l

Onevface of each plate is formed with a Y-shaped slot '66 of relatively narrow depth, and a plurality of such plates are stacked together with a slotted face of each plate contiguous to and contacting a smooth lface of an adjacent plate In this way a plurality of Y-shaped passages 66 are formed in the distributor unit 38o for sub-dividing the gas mixture entering the burner sleeve 25e into a, plurality of gas streams issuing from the ports 65.

The plates 55 include a main body portion 6l at the outermost end of which are formed the lugs 54. From the main body portion 61 projects a head portion 68 of reduced width. The ports 65 are located at a region of the head portion 68 closely adjacent to the shoulder 69 formed in the plates 55 at the juncture of the body portion 6l and head portion 68.

In accordance with my invention, the plates 55 are provided with tabs 'l0 at the extreme end of the head portion 68 to form a protective skirt for the distributor unit 38c, The tabs l0 also form a head portion of such shape that the likelihood of flame extinction is minimized when the burners lc are being operated at reduced capacity.

- The distributor unit 38e is similar to the distributor 38 illustrated in Figs. 3 and 4 in that the individual gas flames brush against and come in contact with the underside and outer surface portions of the tabs l0, thereby heating these regions to incandescence. By providing the tabs 'l0 to form a protective skirt, deposit forming vapors cannot readily come in contact with the. plates 55 at the regions of the ports 65 when such vapors are present in the furnace chamber |90, thereby reducing to a marked degree the depositing of matter in the vicinity of the ports 65.

Figs. 11, l2 and 13 illustrate a still further embodiment which is generally similar to the distributor unit 38e just described and differs therefrom in that, in addition to the tabs '10d similar to the tabs 'I0 in Fig. 10, beveled projections ll are added to the top and bottom edges of the plates I55d at the head portion 68d and between the shoulder 69 and the underside of the tabs 10d. The beveled projections 'll are directly opposite the innermost ends of the Y-shaped passage 66, as shown in Fig. 12, and extend or project outwardly the same distance as the tabs 10d.

Figs. 14 and 15 illustrate a. still further embodiment which is generally like that illustrated in Figs. 11 to 13 inclusive and diifers therefrom in that the projections 'He are tapered and pointed instead of being beveled in the manner shown in Fig. 13.

By adding the beveled projections 'll and lle in the embodiments in Figs. 11 to 15 inclusive, the branch passagesof the Y-shaped slots 66, Which terminate at the opposite side edges of the plates 55, are extended or projected outwardly a distance equal to the depth of the beveled and tapered projections. The beveled projections 7l and tapered projections He permit expansion of the gas as it is being discharged from the Y- shaped slots 66, whereby a more or less streamline ow of the gas streams is effected at the discharge orifices or ports 65d and 65e formed between adjacent projections 1l and Ile. This permits the gases passing* from the slots 66 to expand and completely fill up the ports 65d and 65e and also the immediate regions in the vicinity of the beveled and tapered projections.

-ber spaces cannot pass and come in contact with the distributor surfaces immediately adjacent to the ports 85d and 85e, so that the forming of y a deposit on such surfaces is substantially avoided.

As in the embodiment shown in Figs. 6 to 8 inclusive and described above, a spreading action of the individual burner flames is also obtained by providing the beveled and tapered projections 1I and 11e, respectively, thereby facilitating and promoting rapid uniform heating of the walls of the combustion chamber spaces.

When distributor units 38d and 38e like those just described are operated at a relatively low capacity and tiny flames are produced within the ports 55d and 65e, respectively, such flames rapidly heat the projections vto incandescence,

' thereby promoting and facilitating ignition of the burners under such operation conditions. In addition, the heating of the projections 1i and 'lie to incandescence under the operating conditions just mentioned insures that these regions will always be -maintained at a sulciently high temperature, so that deposits cannot form and accumulate thereon when deposit forming vapors are present. The tabs 10d and 10e at the extremity of the head portion 68 also provide a protective skirt about the ports 65d and 65e, as in the previously described embodiments, thereby providing several forms of distributors for burners of the elongated type which may be used for all heating purposes and especially when it is desired to minimize the risk` of flame extinction and the formation of a deposit when deposit forming vapors are present.

While several embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that various modifications and changes may be made without departing from the spirit and scope of the invention, as pointed out in the following claims.

What is claimed is: 1. The combination with a burner of an elongated type having a refractory wall surface ari ranged to be heated to incandescence by a plurality of flames and from which radiant heat is emitted, such wall surface having an opening leading thereto for the supply of a combustible gaseous mixture, of a distributor unit positioned in the opening, such distributor unit being formed of a plurality of relatively thin plates in stacked relation and including a body portion and a head portion, said plates having slots or grooves therein forming, when said plates are in stacked relation, a plurality of passages extending therethrough .for sub-dividing into a plurality of gas streams the combustible gaseous mixture introduced into the opening, said passages having nlets at the body portion and outlets or discharge ports at the peripheral surface of said head portion at which region the flames are produced and maintained, the outlets or discharge ports being enlarged with respect to the cross-sectional areas of the passages, at the regions thereof extending backward from vthe outlets to the inlets, and formed to provide spaces of such shape that the gaseous mixture passing therein may expand and the velocity of at least a portion of each gas stream is reduced before the gas streams issue from the head portion.

2. The combination set forth in claim l, in which said discharge ports are formed by a plurality of spaced teeth at the peripheral edges of said head portion, said discharge ports being in communication with said passages and adjacent teeth having side Walls diverging from each other toward the extreme peripheral edges of said plates.

3. The combination set forth in claim l, in which said discharge ports are formed by beveled edges at the parts of said plates constituting said head portion.

4. The combination set forth in claim 1, in which said discharge ports are formed by teeth at regions of said plates forming said head portion.

5. The combination with a burner of an elongated type having a refractory wall surface arranged to be heated to incandescence by a plurality of ames and from which radiant heat is emitted, such wall surface having an opening leading thereto for the supply of a combustible gas mixture, of a distributor positioned in the opening, such distributor being formed of a plurality of relatively thin plates in stacked relation and including a body portion and a head portion, such plates having slots therein forming, when said plates are in stacked relation, a plurality of passages for sub-dividing into a plurality of streams the combustible fuel mixture introduced into the opening, said passages having outlets or discharge ports at the peripheral surface of the head portion at which region the flames are produced and maintained, said head portion including a part contiguous to and extending laterally beyond said discharge ports and cooperating with the latter so that the surfaces of each part adjacent to the discharge ports will overhang and be heated to incandescence when the burner is being operated under such fuel mixture delivery pressure Ithat the names contact said part, thereby facilitating and improving ignition of the com- 50 bustible gas mixture issuing from said ports.

6. A distributor for an elongated type gas burner formed of refractory material, such distributor being formed of a plurality of relatively thin plates in stacked relation and including a 55 body portion and a head portion, said plates having slots formed therein to provide a plurality of passages extending therethrough when said plates are in stacked relation, said plates having teeth at the sides of said head portion, adjacent 60 teeth having side walls diverging outwardly toward the surface of the sides of said plates and forming discharge ports communicating with the portions of said passages at said head portion.

7. A gas burner distributor member of re- 65 fractory material for use in a burner of the type described and comprising a cylindrical body portion and two enlarged abutting head portions of which the rst is adjacent and the second more remote from said body portion, respectively, said 70 first adjacent portion of said head being smaller in diameter than said second more remote portion and larger in diameter than said body portion, said member being formed with gas supply grooves each comprising a portion at the periph- 75 ery of, and extending longitudinally of said body portion, each supply groove having an end portion at the side of said first adjacent headportion and extending outwardly to the periphery of said first adjacent head portion.

8. A gas burner distributor member of refractory material for use in a burner of the type described .nd comprising a cylindrical body portion, an enlarged head portion at one end of said member and an intermediate head portion located between said body portion and enlarged head portion and smaller in diameter than the latter and larger in diameter than said body portion, said member being formed 'with gas supply grooves each comprising a portion at the periphery of and extending longitudinally of said body portion, each supply groove having a portion at the side of said intermediate head portion adjacent said body portion and extending to the periphery of saidintermediate portion.

9. A gas burner comprising refractory material shaped to form the wall of a cup-shaped combustion chamber; a gas supply passage having an end thereof communicating with said chamber at the bottom thereof; a distributor of refractory material comprising a cylindrical body portion, an enlarged head portion, and a cylindrical intermediate portion between said body and head portions smaller thanl said head portion and larger than said body portion; said-distributor being formed with grooves, each groove being open at its outer surface and comprising a por-4 tion at the periphery of said body portion and extending longitudinally thereof, and an end portion formed at the periphery of said cylindrical intermediate portion; said passage being formed to receive said cylindrical body portion, so that said head and cylindrical intermediate portions are disposed within and adjacent to the bottom of said cup-shaped combustion chamber and said grooved end portion opens into said combustion chamber between the bottom of said chamber and said head portion.

10. For use inv a Wall of a heating chamber, a gas burner unit comprising a` body of refractory material having a combustion space cavity facing the interior of the chamber, an opening through the wall communicating with the cavity for supplying a combustible gas mixture thereto under pressure, a distributor formed of refractory material having a body portion disposed in the opening and a head portion disposed in the cavity, said distributor having a plurality of grooves on its surface and cooperating with the wall of the openingv head portion adjacent said body portion so that the gas streams will issue from the head portion closely adjacent to and alongsidev of the wall of the combustion space cavity to heat such wall to inlets, vthe gas mixture passing through the enlarged discharge ports expanding before the gas streams issue from the head portion, such expansion of the gas mixture at the discharge ports acting to cause the'gas streams to substantially sweep over the wall surfaces of the discharge ports and the peripheral' surface of the head portion at the regions of the discharge ports to prevent matter from depositing on the head portion which would tend to clog the discharge ports.

11. A burner including 4a refractory block hav-` ing a cavity formed in oneface thereof, said cavity having converging sides that terminatein an opening that .extends through said block, a distributor comprising a body portion received in said opening and a head portion projecting into said cavity, said body being formed with passages of uniform size extending from the end thereof in said opening toward said head, said head being formed with transversely extending passages forming continuations of said rst mentioned passages, the passages in said head increasing in size from said first mentioned passages to the periphery of said head and said head having a smooth portion beyond the passages formed therein extending into said cavity.

' FREDERIC O. HESS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name. Date 968,605 Ruud` Aug. 30', 1910 1,156,845 James Oct. 12, 1915 1,704,875 Vaughn Mar. 12, 1929 1,750,616 McCoy Mar. 11,1930 1,754,603 -Brown Apr. 15, 1930 1,766,803 Scott June 24, 1930 1,932,740 Kerr Oct. 31, 1933 2,215,079 Hess Sept. 17, 1940 2,228,114 Hess Jan. 7, 1941 2,318,985 Baker May 11, 1943 2,339,477 Hess A... Jan. 18, 1944 FOREIGN PATENTS Number Country Date 155,464 Great Britain Dec. 23, 1920 165,471 Great Britain June 20, 1921 191,344 Great Britain 4 Jan. 11, 1923 218,369 Great Britain June 30, 1924 504,738

Great Britain ---2.--- May 1, 1939 

